if (document.images) {
    im1_on = new Image;  im2_on = new Image;  im3_on = new Image;  im4_on = new Image;  im5_on = new Image; 
    im1_off = new Image; im2_off = new Image; im3_off = new Image; im4_off = new Image; im5_off = new Image; 
    im1_on.src = '/images/img_hdr_rifles_on.gif'; im2_on.src = '/images/img_hdr_parts_on.gif'; im3_on.src = '/images/img_hdr_services_on.gif'; im4_on.src = '/images/img_hdr_nfa_on.gif'; im5_on.src = '/images/img_hdr_gallery_on.gif';
    im1_off.src = '/images/img_hdr_rifles.gif';   im2_off.src = '/images/img_hdr_parts.gif';   im3_off.src = '/images/img_hdr_services.gif';   im4_off.src = '/images/img_hdr_nfa.gif';   im5_off.src = '/images/img_hdr_gallery.gif';
  }
  else { 
    im1_on.src = '';  im2_on.src = '';  im3_on.src = '';  im4_on.src = '';  im5_on.src = '';
    im1_off.src = ''; im2_off.src = ''; im3_off.src = ''; im4_off.src = ''; im5_off.src = '';
   }
  function over(objName, flag) { // a function to swap images
    var im = objName; var flg = flag;
    if (flg == 0) { var act = 'on'; }
    else { var act = 'off'; }
    var myImage = eval('document.' + im); // using concatentaion
    var newIm = eval(im + '_' + act); // using concatentaion
    myImage.src = newIm.src;    
  }